Isotopic Fractionation is a physical separation of isotopes and a non-radioactive source of isotope ratios.
However, it is typically unknown and simply assumed whether these ratios of elements are the result of radioactive decay over time or other processes that have taken place in the rock.
Ages of Rocks in Millions of Years Sometimes different methods used on the same rock produce different ages.
To see how we actually use this information to date rocks, consider the following: Usually, we know the amount, N, of an isotope present today, and the amount of a daughter element produced by decay, D*.
By definition, D* = N-1) (2) Now we can calculate the age if we know the number of daughter atoms produced by decay, D* and the number of parent atoms now present, N.
“While an organism is alive and is taking in carbon from the atmosphere, it contains this balanced proportion of 14C.